Mrs Dyson had lived in fear he would one day kill her in a violent rage. And that fear tragically came true in April this year.

Dyson had suffered from depression and post-traumatic stress disorder caused by the premature death of the couple’s 15-year-old daughter and also a rare condition which caused him to believe he was in constant pain.

The judge said the terror, pain and anguish suffered by Mrs Dyson during the attack was “terrible to contemplate.”

Dyson, he said, had told police afterwards that he had “wanted to shut her up.”

“You did so by cruel and merciless strangulation,” said Mr Justice Holroyde. “You are bigger and heavier than her, she stood no chance of defending herself against your murderous attack, which was plainly intended to kill her.”

The judge said it was estimated he applied pressure to her throat for 30 to 60 seconds and possibly longer.

The court heard Mrs Dyson had been running out of patience after caring for her husband for more than 25 years. His constant moaning had left both of them at the end of their tether.

He snapped one day when his wife refused to wait for him to get up when the couple were due to go out. He strangled her with his bare hands and then possibly smothered her with a pillow.

He then walked to nearby Chorley Hospital and told staff “something terrible” had happened. He said he had been in pain for some time and his wife had been “nasty” to him.

The court heard Dyson, who had been violent in the past, but not for many years, then admitted to the police he had killed her.

Officers forced their way into the couple’s home in Harrison Road on April 29. They discovered the body of Mrs Dyson lying on a bed.

A post-mortem examination by a Home Office pathologist found the cause of death was asphyxiation.

Dyson pleaded not guilty to the charge of murder when his case came before Preston Crown Court in September. But he later changed his plea to guilty and the case was sent to Liverpool for sentence.

After yesterday’s hearing Det Insp John Roy, of Lancashire Constabulary’s Major Investigation Team, said: “I welcome the fact that Mark Dyson has admitted the murder of his wife, which has at least spared the family the pain of a trial.

“This is a tragic case and our thoughts remain with the family and friends of Carole Dyson.”

At the time of the murder, neighbours in the quiet residential street at Adlington expressed their shock at the death of Mrs Dyson, who was described as “a lovely woman.”

Audra Ashton, 47, who left flowers at the house as a mark of respect, said: “To me, she was a lovely woman, absolutely fantastic. She had pride in her house and was always out cleaning the windows and cleaning the door.”